Chief Ministers of all states will be invited for the event as GST represented an unprecedented exercise in fiscal federalism, sources said, adding GST Council members will be the guests.

The GST Council had earlier made a decision to relax the deadline for filing of returns for the first two months following GST's rollout.

Speaking about the anti-profiteering laws that were recently cleared by the GST Council on Sunday, Jaitley said that the clause in GST is a deterrent which is not meant to be used unless forced to. The midnight function to launch the GST will be held between 11 PM and 12.10 AM on June 30 effectively ushering in India's new tax regime on July 1.

"Consequently, it should have a positive impact on the GDP", said Jaitley. The size of the formal economy would also increase. "In short term, there will be some challenges in switchover to GST".

The GST Council had on Sunday extended the deadline for filing the first set of returns, a move that will likely soothe frayed nerves of millions of traders. "Process of registrations is going on well", he added.

In other words, the GST will put all taxes levied by state and Central government in one basket and merge them into a single-tax system, thus doing away with multiple taxation and promoting the concept of a common market for all. "Kerala govt will pass SGST this week", Jaitley told reporters during a press conference.